Year	Percent
1980-01-01	23.180850000000000
1981-01-01	25.374589999999998
1982-01-01	22.625429999999998
1983-01-01	22.743879999999997
1984-01-01	22.076490000000000
1985-01-01	23.073339999999998
1986-01-01	23.320900000000000
1987-01-01	24.322350000000000
1988-01-01	25.305520000000000
1989-01-01	29.575870000000002
1990-01-01	42.892470000000000
1991-01-01	31.000020000000003
1992-01-01	20.953440000000000
1993-01-01	12.769650000000000
1994-01-01	11.857060000000000
1995-01-01	14.355479999999998
1996-01-01	16.108800000000000
1997-01-01	17.742440000000000
1998-01-01	18.596729999999997
1999-01-01	18.320030000000000
2000-01-01	17.272010000000000
2001-01-01	16.504200000000000
2002-01-01	17.858580000000000
2003-01-01	17.658350000000000
2004-01-01	18.631790000000000
2005-01-01	21.727240000000000
2006-01-01	24.188760000000002
2007-01-01	26.391930000000000
2008-01-01	26.842300000000000
2009-01-01	31.374890000000000
2010-01-01	32.309850000000000
2011-01-01	32.009029999999996
2012-01-01	31.696279999999998
2013-01-01	31.806240000000003
2014-01-01	32.323940000000000